1. Field of the Invention
The disclosure generally relates oilfield applications having a pumping system. More particularly, the disclosure relates to oilfield applications having a pumping system that intermixes at least two incoming fluids for fracturing operations.
2. Description of the Related Art
FIG. 1A is an exemplary schematic diagram of a prior art fracturing system for an oilfield fracturing operation. FIG. 1B is an exemplary schematic diagram of a prior art fracturing system, showing fractures in an underlying formation. FIG. 1C is an exemplary schematic diagram of the prior art fracturing system of FIG. 1A detailing a system for one well. The figures will be described in conjunction with each other. Oilfield applications often require pumping fluids into or out of drilled well bores 22 in geological formations 24. For example, hydraulic fracturing (also known as “fracing”) is a process that results in the creation of fractures 26 in rocks, the goal of which is to increase the output of a well 12. Hydraulic fracturing enables the production of natural gas and oil from rock formations deep below the earth's surface (generally 5,000-20,000 feet). At such depths, there may not be sufficient porosity and permeability to allow natural gas and oil to flow from the rock into the wellbore 22 at economic rates. The fracture 26 provides a conductive path connecting a larger area of the reservoir to the well, thereby increasing the area from which natural gas and liquids can be recovered from the targeted formation. The hydraulic fracture 26 is formed by pumping a fracturing fluid into the wellbore 22 at a rate sufficient to increase the pressure downhole to a value in excess of the fracture gradient of the formation rock. The fracture fluid can be any number of fluids, ranging from water to gels, foams, nitrogen, carbon dioxide, or air in some cases. The pressure causes the formation to crack, allowing the fracturing fluid to enter and extend the crack further into the formation.
To keep the fractures open after the injection stops, propping agents are introduced into the fracturing fluid and pumped into the fractures to extend the breaks and pack them with proppants, or small spheres generally composed of quartz sand grains, ceramic spheres, or aluminum oxide pellets. The proppant is chosen to be higher in permeability than the surrounding formation, and the propped hydraulic fracture then becomes a high permeability conduit through which the formation fluids can flow to the well.
In general, hydraulic fracturing equipment used in oil and natural gas fields usually includes frac tanks with fracturing fluid coupled through hoses to a slurry blender, one or more high-pressure, high volume fracturing pumps to pump the fracturing fluid to the well, and a monitoring unit. Associated equipment includes fracturing tanks, high-pressure treating iron, a chemical additive unit (used to monitor accurately chemical addition), pipes, and gauges for flow rates, fluid density, and treating pressure. Fracturing equipment operates over a range of pressures and injection rates, and can reach up to 15,000 psi (100 MPa) and 100 barrels per minute (265 L/s). Many frac pumps are typically used at any given time to maintain the very high, required flow rates into the well.
In the exemplary prior art fracturing system 2, fracturing tanks 4A-4F (generally “4”) deliver fracturing fluids to the well site and specifically to one or more blenders 8. The tanks 4 each supply the fluids typically through hoses 6A-6F (generally “6”) or other conduit to one or more blenders 8. One or more proppant storage units 3 can be fluidicly coupled to the blenders 8 to provide sand or other proppant to the blenders. Other chemicals can be delivered to the blenders for mixing. In most applications, the blenders 8 mix the fracturing fluids and proppant, and delivers the mixed fluid to one or more trucks 5A-5E (generally “5”) having high-pressure pumps 9A-9F (generally “9”) to provide the fluid through one or more supply lines 10A-10E (generally “10”) to a well 12A (generally “12”). The fluid is flushed out of a well using a line 14 that is connected to a dump tank 16. The fracturing operations are completed on the well 12A, and can be moved to other wells 12B and 12C, if desired.
FIG. 2A is an exemplary side view schematic diagram of a prior art goat head. FIG. 2B is an exemplary top view schematic diagram of the prior art goat head of FIG. 2A. FIG. 2C is an exemplary perspective schematic view of an installation of the prior art goat head of FIGS. 2A-2B on a well. The figures will be described in conjunction with each other. A “goat head” 20 is known to be a large block of steel for mixing fluids. The goat head is placed on top of a well 12, resulting in an elevation of about 14-16 feet (5 meters) from the ground. The goat head 20 has a top 21 and a bottom 23 and multiple fluid inlets 28A-28E (generally “28’). Traditionally, the fluid inlets are directed upward toward the top of the goat head, where the supply lines attached to the top inlets resemble “horns” from the top of the “goat head.” The inlets 28A-28E allow the fluids to be combined from the multiple supply lines 10A-10E shown in FIG. 1C into a central bore 27 for mixing. The combined flow is directed downward through an outlet 25 into the well 12.
The flow path from the top 21 of the goat head downward into the well 12 is an accepted practice for the industry to reduce pressure losses by reducing the bends and turns of fluid flow. The top-to-bottom flow path also reduces erosion from the sand and other proppants on the goat head bore and other flow surfaces, and increases service life.
One of the significant challenges in fracturing operations is the large number of trucks, pumps, containers, hoses or other conduits, and other equipment for a fracturing system. The system of FIG. 1C is vastly simplified as only showing a few trucks with only one well. In practice, many trucks and pumps are used to provide the cumulative amounts of fluid for the well at a well site which are moved from well to well. The difficulty of working around the wells with the large number of components also causes safety issues.
Recently, efforts in the industry have been directed to more efficiently fracture multiple wells at a given field. The number of assembled equipment components has raised the complexity level of the system and the ability to operate in and around the multiple wells. One of the improvements needed is an improved goat head assembly.